login: ignore SIGXFSZ when write to lastlog

the lastlog file is huge and on systems with large UIDs, it's so huge that
it generates SIGXFSZ when the FSIZE limit is too small.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1165702
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/login-utils/login.c b/login-utils/login.c
index ebb76f5e97e05dc02b3554e14b82163e42399388..5546435593ef5117df94d16c7ea2f201f9aa6796 100644 (file)
--- a/login-utils/login.c
+++ b/login-utils/login.c
@@ -495,6 +495,7 @@ static void log_audit(struct login_context *cxt, int status)
 
 static void log_lastlog(struct login_context *cxt)
 {
+       struct sigaction sa, oldsa_xfsz;
        struct lastlog ll;
        time_t t;
        int fd;
@@ -502,9 +503,14 @@ static void log_lastlog(struct login_context *cxt)
        if (!cxt->pwd)
                return;
 
+       /* lastlog is huge on systems with large UIDs, ignore SIGXFSZ */
+       memset(&sa, 0, sizeof(sa));
+       sa.sa_handler = SIG_IGN;
+       sigaction(SIGXFSZ, &sa, &oldsa_xfsz);
+
        fd = open(_PATH_LASTLOG, O_RDWR, 0);
        if (fd < 0)
-               return;
+               goto done;
 
        if (lseek(fd, (off_t) cxt->pwd->pw_uid * sizeof(ll), SEEK_SET) == -1)
                goto done;
@@ -542,7 +548,10 @@ static void log_lastlog(struct login_context *cxt)
        if (write_all(fd, (char *)&ll, sizeof(ll)))
                warn(_("write lastlog failed"));
 done:
-       close(fd);
+       if (fd >= 0)
+               close(fd);
+
+       sigaction(SIGXFSZ, &oldsa_xfsz, NULL);          /* restore original setting */
 }
 
 /*